Electric switch



'Dec. 25, 1928.

J. D. HILLIARD ELECTRIC SWITCH Filed Jan. 2, 1924 Inv-er1 t ov JahnD.Hi||ia1^d) His Attorneg.

Patented Dec. 25, 1928.

UNITED STATES JOHND. HILLIARD, 0F SCHENECTADY, NEW YORK, ASSIGNOR TOGENERAL ELECTRIC I COMPANY, A CORPORATION OF NEW YORK.

PATENT OFFICE.

ELECTRIC SWITCH.

Application tiled January 2, 1924. Serial No. 684,003.

My invention relates to electric switches, particularly those forcontrolling high potential currents of large capacity. i

For the control of high potential power circuits, switches of the oilbreak type heretofore have been almost universally employed and as tothe development of the art \under a heavy load, the switch contacts andoil have been enclosed in strong steel tanks capable of withstanding the`high pressures generated in order to avoid the loss of oil and the riskof fire and personal injury. Not only is the cost of manufacture of suchapparatus excessive but because of its size serious transportationldiliculties often arise in placingv the apparatus after it ismanufactured.

It is an object of my present invention to provide a construction ofswitch for con` trolling high voltage circuits which shall avoid vtheYabove mentioned dangers, shall comprise parts of moderate dimensionsfacilitating transportation, shall be manufacturablc at a relatively lowcost and beI efficient in operation.

My invention willlbe better understood by reference to the accompariyinspecification and drawing andt'its scope will be pointed out in theappended claims,

In the drawing, Figure 1 isla simple diagrammatic sketch showing 'the'gist of the invention and Fig. 2 is a more complete diagrammaticVshowing of -one manner of carrying out the invention. y v

Before proceeding with the detailed description, I desireto point outthat in illustrating my invention, I have made no attempt to show' thevarious parts in their relative proportions but, in a diagrammaticmanner only.

Referring `first to Fig. 1 of the drawing where I have showndiagrammatically the more essential features ofmy invention, the mainbreak in the circuit to be controlled is between contacts 1 and 2 ofwhich the 'line in Fig.` 1.

former is shown as a stationary socket and the latter a downwardlymovable rod. The stationary contact l` is located above an open v essel3 of comparatively. small diameter and of insulation containing a liquid4 of fairly high dielectric strength through which the movable contact 2projects and is adapted to be moved vertically into and out of contactwith the stationary contact. For moving contact member 2, it is shownprovided with a piston head 5 which is adapted to slide in a cylinder 6,the cylinder being connected at a point above the piston by a pipe 7leading to a pressure device. .Pressure for operating the piston isobtained by a preliminary interruption of the circuit at a point otherthan at the main contacts and in a medium which will be vaporized ordisassociated to form a gas Orvgases. According to Fig. l this may beaccomplished by providing a lswitch having a movable contact 9 and astationary contact l0 mounted on an insulator 11 in the bottom of theclosed vessel 12 which is filled with al liquid which will produce a gaswhen sub- ]ected to the vaction of an are and which is connected wth thecylinder 6 by the pipe 7. This pipe should be of sutlicient size tofreely transmit pressure to vessel 6. The movable member 9 of the switchis shown attached to the plunger 13 of the series solenoid 14 vof which'one terminal connects with the line to be controlled while-the otherterminal connects with stationary contact l0. The movable contact 9 isin elec` trical connection with the main contact 2, such connectionbeing indicated by a dotted Supposing both sets of contacts to be inclosed circuit position and contact 1 to be connected to the line, anoverload current of a predetermined value will actuate the solenoid 14to separate contacts 9 and 10 and draw an arc in the closed vessel 12.The resulting vapor or gas produced being communicated to the cylinder 6causes a rapid downward movement of the piston 5 and attached contactrod 2. Thus the circuit is opened between contacts 1 and 2 whichconstitutes the main break and an arc is quickl drawn first through theair aloneand nally into the insulating liquid contained in the vessel 3.Because of the small diameter of the vessel 3, the sudden formation ofgas therein Causes a stream of cool liquid to be thrown directly intothe arc. The-break produced by the operation of switch 9 is intended toeffect only a partial interruption of the line circuit and while it thusassists in the final interruption of the circuit its principal object isthe production of-an arc ina liquid which will be vaporized ordisassociated for the purpose of generating sui-table pressure toactuate the main Switch rod 2.

Having thus briefly explained the chief characteristics which constitutethe gist of one feature of my invention by means of the diagramcomprising Fig. 1 of thedrawing, I shall now proceed to describe ingreater detail, by the aid of the diagram 4comprising Fig. 2, apparatuswhich might be used to carry out my invention.

The switch being adapted for the. control' of a high potential circuitobviously must be supported in such a mannerl as to be thoroughlyinsulated from the ground. The operating mechanism of the switch beingactuated as a result-of the sudden generation of gas pressure," in thenature of an explosion, the insulating supports will be subjected tosevere shocks and vibrations which, as is well known to those skilled inthe art, are not adapted tobe successfully withstood by rigid insulatorsupports such for example asv porcelain. In Fig. 2 I have shown theAentire switch mechanism suspended from anV overhead frame work byflexible insulators ofthe sus ension t e'whereby the shocks andvibrations inci ent to the operation ot' the mechanism may be absorbedor dissipated without injury to the .insulating means. v

A truss 16 is shown resting at its ends on cross channels 17 which inturn are supported on standards 18. Near each end of the truss hangs aninsulator string 20 whose lower end carries a cross member 21.Intermediate the ends of the insulator string, a cross member 22 issecured, at one end of which a connection is made to the line as at 23and at the midpoint of which the covered stationary contact is attached.This contact may be of any suitable form to frictionally engage the rod2 as for example the contact shown in the patent to E. W. Rice #812,880.Suspended from the member 21 is the cylindrical metal vessel 6, securedinto the top of which is the small vessel 3 ofinsulating material. Thepiston 5 fits the vessel 6 and has secured tof it the contact rod 2which extends up through the vessel 3 to en age the stationar contact 1.Contacts 25 attached to a partition 26 'in -vessel 6 serve to provide agood lelectrical connection between that member and the Contact rod 2.The vessel 6 is closed at its lower end by a cap 27 and near that end isprovided with a series of longitudinal slots 28, In the region of theslots 28, the vessel 6 is shown surrounded forming therewithA a closedreceptacle which communicates through a plurallty of pipes,diagrammatically Villustrated by a single pipe 30, with a reservoir 31situated on the cross bar 21. The vessels, the pipe and the reservoirthus far described may .be filled to the level indicated with a suitableliquid such for example'as water, a mixture of water and glycerine orother liquid having a fairly high dielectric strength. Withthe pistonand rod in 'the position illustratedvit will be readily apparent ifpressure is'admitted to the vessel 6 below the partition therein thepiston and rod will beM forced down thereby breaking connection with thestationary contact'l and coming to rest slow' to the atmosp ere andasmall tube 34 ,leads to a reservoir` 35, the same liquid being used inthe closedvessel 12 and reservoir 35 as in the vessels 6 and 3. Theswitch 9 is Velectrically connected with the chamber l 12 throughbrushes 37 while the stationary, cooperating contact 10 is insulatedtherefrom by insulator bushing 11. `The contact 9 is connected to core`13 and adapted to be moved to open circuit position by the solenoid 14.The solenoid 14 is shown normally shunted by a switch 38 which isadapted to bev opened by 'a solenoid A39 Whenever the current in theline reaches a predetermined value. The line to be controlled may beconnected by lead 23 to -the cross member 22- and from the solenoid 1 awire 40 may lead to a disconnecting switch shown diagrammatically at 41and from thence to the line by wire 42. The contact rod 2 is heldfrictionally in its upper or circuit closing position and inorder thatit may be returned to that position after havin been actuated to openthe line circuit, sui able means, vas

.for example, a rod 44 may be provided which passes up through astufiingy box 45 in the cover 27. Rod 44 has an insulation section 46therein and a handle 47 at its lower end.

To enable the main switch tobe'ope'ned manually, the piston 5 is shown'carrying .a

vcollar 49 having a bayonet slot therein in which a small cross rod 50at the upper end of rod 44 is adapted to engage,

Although I have shown and described apparatus for interrupting thecircuit through a single conductor o r phase it will by a second casing29 of larger diameter be understoodthat I contemplateproviding duplicateapparatus to be suspended from a truss similar to that shown at 21 andsupported in arallel relation therewith for the control o a metalliccircuit single phase transmission line. Likewise for the control of athree phaseline I may use the same apparatus in triplicate. In eithercase'the standards or towers 23 would be suitablyv positioned so as notIto interfere with the mechanism.

The' operation of the more complete mechanism which I have. illustratedby way of example in Fig. 2 is as follows: Assuming the parts tol be in'the. -relative positions shown by the drawing, the line current may beconsidered to enter at the connection 23, pass through the member 22 tocontact'l, to rod 2, through contacts 25 to member 6 through supportingmember 21 and pipe 7 to vessel 12 to switch rod 9. From t tionary.switch contact 11 it passes to the solenoid 39, through .switch 38 towire 40 to disconnecting switch 41 to the lineby wire 42. Normal valuesof line current are 'insufficient to operate the solenoid 39 but uponthe occurrence of a predetermined overload th solenoid 39 will-open theswitch 38 thereby causing the operation of solenoid 14 and 'an openingof the switch 9. Thearc drawn by the opening df this switch suddenlygenerates a considerable Aquantity of gas-in thechamber 12 and since thevent tube 33 and the reservoir tube 34 provide only restricted outl tsfor the escape of gas vand liquidfthe resu ting pressure in the chamber12 is releved principally4 by the pipe 7 leading to the vessel 6. Piston5 is immediately vforced down, the rod 2 breaking connection withcontact 1 and opening the main circuit. The arc of the main break isthus drawn first through air and then as the end of the rod 2 becomessubmerged upon continued downward movement, the arc is also drawnthrough the liquid in the cylinder-3. As

vthe piston moves downwardly the li uid beneath it is forced out throughthe s ots 28, through pipe 30 into reservoir 31. After the pistonreaches the upperv ends'of the slots 28 the escape of liquid. becomes,more and more restricted until, and when the piston reaches 'its lowerlimit,`the slots 28 are entirely closed. A gradual checking of themovement of the iston and contact rod is thereby effected. After themain circuit has been broken as described above the. disconnect switchmay be opened. It will be noted that the switch 9 in the chamber 12 isfree to close by gravity when the line circuit is finally opened.

The main contact rod 2 may be raised to closed circuit position bypushing up on the rod 44, the rod 2 being frictionally held in closedcircuit position. Likewise the rod 2 may be lowered by hand to open theswitch manually by first raising the rod 44 and e sta- Vandv movab ecooperating contacts, fluid pressure actuated operating means therefor,fiexible insulating means connected at its lower end with the movablecontact and the operating means for freely suspending the same from saidstructure and means secured to the yflexible insulating means at a pointintermediate its ends for supporting the stationary contact.

2. A high' potential switch comprising a stationary contact, a vesselcontaining in- 'sulat-ing liquid below said stationary contact, amovable contact vadapted to -extend up through' saidA liquid to engagesaid stationary Contact, means for drawing an arc in aninsulating fluid,to produce a fluid pressure, and means actuated by said fluid pressurefor withdrawing said movable contact'from said stationary contact to aposition below the level of said liquid.

3. A high potential switch mechanism comprising a main switch, anauxiliary switch having contacts separable in a liquid convertible intogas by the arc` formed upon the separation of its contacts, and meanswhereby the gas pressure produced by the opening of said auxiliaryswitch moves the main switch to open circuit position.

4. An electric switch comprising a stationary contact, a narrow openreceptacle spaced below the stationary contact and containing insulatingliquid, a contact rod mounted centrally iu said receptacle and movablethrough the bottom thereof, and means for quickly withdrawing thecontact rod from the stationary contact, through the intervening spaceto a position below the surface of the liquid in the receptacle.

5. An electric switch mechanism comprising a pair of relatively movablecontacts, a closed vessel containing a liquid, a second pair ofrelatively movable contacts in said liquid adapted to draw an arc whenseparated and means responsive to the pressure in said vessel producedby said are for separating said first contacts.

Y 6. An electric switch mechanism comprisinga pair of relatively movablecontacts. pressure actuated means for separating said contacts. a closedvessel containing liquid, a second pair of contacts immersed iu saidliquid adapted when opened to draw an arc in the liquid and create apressure in the vessel, and means for communicating said pressure tosaid pressure actuated means.

7. An electric switch mechanism comprising a stationary contact, anarrow open vessel Containing insulating liquid spaced bcneath saidcontact, a 'cooperating movable contact rod mounted to extend upcentrally through the liquid in said vessel, a fluid pressure operated'member on said rod adapted to withdraw the rod from the stationarycontact to a position beneath the surface of the liquid and loadresponsive means for subjecting said member to fluid pressure.

Inwitness whereof, have hereunto set my hand this 31st day of December,1923.

A JOHN D. HILLIARD.

